Just how many cores for a wired burglar alarm?

[Handymanjo]

Good luck getting your bell box working with 3 core!!!!!
You will now have to spent time and effort running another cable
6 core or 8 core does the job every time.
If you concentrated on getting the job done instead of all this detail that the average diy person does not understand YOU mite get it right

 

[PaulUszak]

The bell / siren would normally be fed from a local battery

This is interesting. My bell boxes can operate without the internal battery connected. In fact, there is a factory jumper to specifically disconnect the internal battery. As the horns blare and the lights flash without a battery in place, that would then suggest the power is coming from the main control panel. These were Reson8 bell boxes originally. The stock battery is actually 6V not 9V. I don't know for sure whether there is a buck converter on board as I wasn't that interested. There is a large power semiconductor and a transformer so there might be, unless it's impedance matching for the piezo transducer but that seems unlikely. Should have clipped on the oscilloscope to read the voltage at the transducer I guess.

It would be great if the boxes could power themselves, but unfortunately my design would exceed the capacity of the stock circuitry. I need another 2000mA above the normal capacity as I have upgraded strobes. Hence the thicker wires. Anyway, isn't more better?

 

[bernardgreen]

here is a factory jumper to specifically disconnect the internal battery

Why is that link there ? If it wasn't there to isolated the battery then how could the bell box stored before being installed ?.

If you leave the battery dis-connected then ensure the cable to the bell box cannot be cut because if it is cut then the bell / siren cannot be sounded when the house is broken into.

but unfortunately my design would exceed the capacity of the stock circuitry.

Lets hope it actually works as a burglar alarm when it needs to do that.

 

[Europlex]

Three cores, interesting, please tell us how you do that.

How about this then, my bell boxes can operate on two wires, beat that.

 

[Europlex]

I'm waiting for someone to come up with a way to work them on one wire, I'll be able then to use up all the lace wire I've got in the shed.

 

[secureiam]

wants to use less cables for some reason modifies the bells so he needs another 2A of power just for the strobes?

Think its more a pet project than a well thought out alarm system?

 

[Handymanjo]

Don't forget he wanted EOL on his Honeywell G4(metal version) and also didn't want a global tamper ?
Now his 3 wire bell box will not have a tamper return?
Opps why do alarm systems have a tamper circuit.
This will be a burglars delight !!!!
Alarm goes off fuses blow on panel due to over load on bell circuit with up rated strobe light?

 

[sparkymarka]

Is this ericmark ? Lol

 

[PaulUszak]

Lets hope it actually works as a burglar alarm when it needs to do that.

Tested and working fine, thanks. You do need sunglasses and ear plugs when you're running both bell boxes on the bench though.

 

[PaulUszak]

Think its more a pet project than a well thought out alarm system?

Can you imagine a scenario where it's both?

 

[bernardgreen]

Alarm goes off fuses blow on panel due to over load on bell circuit with up rated strobe light?

Tested and working fine, thanks. You do need sunglasses and ear plugs when you're running both bell boxes on the bench though.

When you tested the system how long did you have the bell boxes running ? Are you 100% certain that the fuses will carry the current long enough for people to realise the alarm is sounding before the fuse melts. ? That is part of the work in designing a reliable item.

Can you imagine a scenario where it's both?

If the designer has the necessary knowledge and skills then yes.

 

[Europlex]

I'm getting confused here, could you please confirm what each of your 3 wires do? Thank you.

 

[PaulUszak]

Alarm goes off fuses blow on panel due to over load on bell circuit with up rated strobe light?

Very well done for spotting that. There’s an obvious way to obtain the additional current I need. Can you guess? Hint, there’s a high current source within the main control panel that begins with the letter “B”

 

[PaulUszak]

Europlex, this is the mod. Apologies for it's scrappy nature, my schematic package has thrown a wobbler.

//www.diynot.com/diy/media/alarm.97966/


So there are 2 bell boxes with each with 3 core cable. The reason that there is only one core for both the strobe and the sounder is that the strobe latches on my panel. If the alarm went off when we were away, it would continue to strobe for hours. I can't allow that with the strobes I have ( http://www.redtronic.co.uk/bx61-grille-lamps.html ), especially at night being blue.

The flyback diode isn't required.

I'm thinking of replacing the relay with a P channel MOSFET as the 12V signal should easily exceed the gate threshold voltage and there are no issues with switching frequency. I shouldn't therefore need a driver, just a simple swap out.

Wired alarm panels were never designed for modern all in one bell boxes, so connection to separate bell and strobe was common. You can still see the evidence for this in the layout of the connectors and the specification in the engineer's guide. I'm just going retro...

 

[PaulUszak]

fuse melts

Only ran them for 2 minutes. The total current draw is 2250 mA (a little difficult to measure) and I've fused for 6.3A fast. Hmm, perhaps I should lower that.